No, not undo the damage our actions had caused - for that we'd need a time machine - but rather erase painful memories of the past.

It may seem like the stuff of science fiction, but researchers have made great progress in recent years in understanding the neural processes and bio-chemistry involved in memory formation and recall.

So much so that some are beginning to talk about cures for phobias and treatments for post traumatic stress disorder.

Tetris playing uses similar brain areas to trauma recall

In her work on PTSD at Oxford University's Institute of Psychiatry, Dr Emily Holmes is no stranger to haunting imagery, or the harm such vivid flashbacks can cause.

In a remarkable experiment involving footage taken at the scenes of car crashes and clips of old public information films, Dr Holmes is using the computer game Tetris to disrupt the processes in the brain involved in laying down painful memories, dramatically reducing the impact of recalled trauma.

"The biology of memory suggests you've got about six hours after a traumatic event while that memory solidifies," she says.

"What we wanted to find was whether we could do something to disrupt that process of memory formation".

Memory block

Dr Holmes played clips of traumatic events, including a child drowning, to 40 volunteers.

While one group was asked to sit quietly after viewing the films, another played the computer game Tetris.

We will be able to figure out which neural networks underpin certain memories, and to undermine them

Anders Sandberg

The results showed that the volunteers who played Tetris experienced about half as many flashbacks as the control group, and that those memories were less vivid or disturbing.

The point about Tetris, Dr Holmes concludes, is that it employs many of the same areas of the brain - to do with visual processing and coordinating thoughts and actions - that are involved in laying down memories.

"Disrupting those functions by diverting the brain's attention in this crucial six-hour window seems to dampen down the vividness of memory," she explains.

Many of the recent advances in our understanding of the brain have come from the field of neural imaging. Functional MRI scanning and EEG have allowed scientists to monitor the activity of the brain while patients complete complex mental tasks.

But understanding which areas of the brain are involved in laying down memory tells you little about the bio-chemical processes involved.

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To understand that Dr Todd Sacktor and his team at the State University of New York have been investigating the glue-like role that a particular protein - known as KPM-zeta - plays in the consolidation of memory at specific synaptic points in the brain.

By interrupting the process with another drug - Zip - Dr Sacktor's team was able to erase the memory of a mild electric shock in rats. It's the first step, Dr Sacktor claims, in chemically controlling unwanted or intrusive memories.

"The key thing is that once the drug wears off, which happens within a couple of hours, the memories never come back. So it seems to be a true erasing".

'Ethical problems'

It's an exciting prospect. One which holds out hope of tangible relief for those suffering from traumatic or intrusive flashbacks.

But what does it mean for our identity and humanity? Who we are is the product of a lifetime's accumulated experience, and the memories - good and bad - of that journey.

The rights and wrongs of erasing memory will be debated by some of the leading researchers in the field tonight at a debate organised by the Wellcome Collection.

New techniques in brain scanning are opening a window on the brain

Speaking on the programme this morning, Anders Sandberg from the Future of Humanity Institute at Oxford University said nobody should object to efforts to help people suffering from serious psychiatric conditions like PTSD.

But in the future, "we will be able to figure out which neural networks in the brain underpin certain memories, and to undermine them. That's going to cause some ethical problems".

The philosopher Anthony Grayling points out that we do erase some traumatic memories - ones which are simply too painful to face - naturally, but on the whole it matters tremendously that we should retain our memories, even the bad ones.

"Memory is a very important component of our person-hood, our self-hood. We are what we are because of all the experiences we've had".

If you had the option to erase bad memories, would you? Let us know your thoughts on the neuroscience of memory using the form below.

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